Catalases play a pivotal role in detoxification and cellular defense against oxidative stress. Laccase 2, a phenoloxidase gene was also induced in bergapten-fed bruchids. Presumably oxidative crosslinking may help decrease bergapten penetration of insect midgut. Furthermore, among bergapten-induced genes were several that are associated with disease resistance. The drosomycin-like genes are of central importance in the insect immune system against bacterial infection. Notably, they are also repressed by scN. On the contrary, many genes involved in protein, lipid and carbohydrate digestion were suppressed under bergapten treatment, opposite to their responses to scN. The antagonistic effect of scN and bergapten on the vast majority of coregulated genes is intriguing. Possibly, scN is able to prevent bergapten-induced adaptive transcriptional adjustment, and even to synergize bergaptens anti-insect activity. To investigate the potential interaction between bergapten and scN in the insect midgut, a combination of both chemicals were incorporated into the artificial seeds to test their effect on GANT61 500579-04-4 development of the insect. Bergapten at 250 ppm exhibited a mild but significant effect on the development of the bruchids. scN at 1,000 ppm showed no significant effect by itself, yet further delayed bruchid development by 2 days in the combination treatment when compared to the bergapten treatment. qRT-PCR of 11 selected genes validated the microarray results associated with bergapten treatment. Although scN alone, at the concentration we chose, did not cause any apparent change in insect development, it was sufficient to alter transcript abundance of the selected genes, the profile of which is in agreement with cDNA microarray results. These bergapten- and scN- coregulated genes include those potentially involved in carbohydrate and protein degradation, disease resistance, and stress tolerance. Antagonistic regulation has been observed for many of these genes, that is, genes induced by scN but repressed by bergapten, or vice versa, had much lowered induction or suppression in the combinatory treatment compared to individual chemical treatments. Since insect adaptation to dietary challenges is at least in part mediated by transcriptional regulation, attenuation of bergapten-induced transcriptional adjustment by scN among genes of broad functionality could be responsible for their synergistic anti-insect activity. Out of 80 coregulated genes with BLAST hits, the only two that showed the same transcript regulation by scN and bergapten did not result in further induction or suppression. Deploying secondary metabolites is a common defense mechanism used by many plant species to fight against insect AMN107 cost herbivory. Here, we tested dietary bergapten for its effect on a coleopteran storage pest and found that it negatively impacted development, reproduction and survival of cowpea bruchids.